Siemens SIMATIC ET 200AL System Manual page 1181

Functions
5.9 Standard machine projects
Explanations and recommendations concerning the rules
● If you do not list an IO device to be configured as optional IO device in the control data
record or data block resp. this IO device does not form part of the configuration and does
not take part in data exchange with the CPU.
● If you do not activate any optional IO device at all and work with the loaded configuration
without reconfiguration, you still have to follow the proceeding described in the above
section and transmit the control data record to the CPU.
The control data record has the simple structure with the following tags:
– Version (High Byte =1, Low Byte = 0)
– Number of optional devices to be activated = 0
– Number of port interconnections that are set in the user program = 0
● Following a STOP > RUN transition and following a POWER-OFF > POWER-ON
transition, all IO devices are deactivated automatically. For this reason, no
ReconfigIOSystem call with MODE 1 is required for configuration control to function
properly.
If you use your project as a universally valid sample for programming the configuration
control, we still recommend to perform the ReconfigIOSystem call with MODE 1 prior to
any reconfiguration. This way, the sample can also be used for reconfigurations in RUN
mode.
● Commissioning extensive I/O systems (more than 8 optional IO devices) while using IRT
at the same time:
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PROFINET with STEP 7 V15
Function Manual, 12/2017, A5E03444486-AH